Evaluation of amplitude encoded fringe patterns using the bidimensional empirical mode decomposition and the 2D Hilbert transform generalizations

Abstract

We propose an application for a bidimensional empirical mode decomposition and a Hilbert transform algorithm (BEMD-HT) in processing amplitude modulated fringe patterns. In numerical studies we investigate the influence of parameters of the algorithm and a fringe pattern under study on the demodulation results to optimize the procedure. A spiral phase method and the angle-oriented partial Hilbert transform are introduced to the BEMD-HT and tested. A postprocessing filtration method for BEMD-HT is proposed. Results of processing experimental data, such as vibration mode patterns obtained by time-average interferometry, correspond richly with numerical findings. They compare very well with the results of our previous investigations using the temporal phase-shifting (TPS) method and the continuous wavelet transform (CWT). Not needing to perform phase-shifting represents significant simplification of the experimental procedure in comparison with the TPS method.